Dani Pedrosa completed a free practice sweep during day one of the US MotoGP at Laguna Seca on Friday.

Having put the new version of the Honda RC213V at the head of the field this morning, Pedrosa lowered his best lap time by a further 0.4s during this afternoon's interrupted session.

Red flags were waved following an accident for Valentino Rossi with ten of the 45 minutes remaining. The Italian was dumped onto the asphalt when he lost the front on entry to turn three.

Rossi walked away but his Ducati damaged the airfence, forcing the session to be halted until repairs were complete.

Pedrosa was leading by the time of the stoppage, having set his 1m 21.088s best on lap 11 of 23 and the top four places were unchanged after the restart.

As this morning, Yamaha's world championship leader Jorge Lorenzo was closest to Pedrosa, finishing the session 0.334s behind. Lorenzo currently holds a 19-point lead over nearest rival Pedrosa.

Pedrosa's team-mate Casey Stoner repeated his morning third, this time just 0.035s from Lorenzo, despite running off track after the restart when he caught CRT wild-card Steve Rapp at the wrong time and was forced to lift his RCV upright.

Ben Spies, who announced earlier this week that he will leave Yamaha at the end of the year, retained fourth (+0.620s) to be the fastest American. Spies will be targeting his first US GP podium on Sunday.

Monster Yamaha Tech 3 riders Andrea Dovizioso and Cal Crutchlow did improve in the closing minutes for fifth and sixth, again repeating their morning positions. Crutchlow, who finished 1.170s from Pedrosa, fell at high speed through turn ten just before Rossi's accident.

The first position change relative to FP1 came for seventh place, with the newly re-signed Nicky Hayden taking the place from team-mate Rossi this afternoon. Rossi slipped back to ninth (+1.684s) with Honda LCR rookie Stefan Bradl once again splitting the factory GP12 riders.

Gresini's Alvaro Bautista fell at the same corner as Rossi on his way to tenth place, with Aleix Espargaro the leading CRT competitor in eleventh. The Aspar rider was just under one-second from Bautista and 2.7s from Pedrosa.

Team-mate Randy de Puniet and Texan Coin Edwards (Suter-BMW) followed, with Pramac stand-in Toni Elias gaining one place relative to his morning position. Karel Abraham, making his return from injury, was the slowest of the manufacturer riders in 16th place for Cardion AB Ducati.

All 22 riders improved their lap times this afternoon, including Rapp, who cut the gap to Pedrosa from 8.3s to 6.9s on his Kawasaki-powered Attack Performance machine - but was still 1.3s outside the hypothetical (for free practice) 107% qualifying time.

Third practice takes place on Saturday morning. As usual, the Moto2 and Moto3 classes are not present at Laguna Seca.

Friday practice (2):

1. Dani Pedrosa
2. Jorge Lorenzo
3. Casey Stoner
4. Ben Spies
5. Andrea Dovizioso
6. Cal Crutchlow
7. Nicky Hayden
8. Stefan Bradl
9. Valentino Rossi
10. Alvaro Bautista
11. Aleix Espargaro
12. Randy De Puniet
13. Colin Edwards
14. Toni Elias
15. Yonny Hernandez
16. Karel Abraham
17. Mattia Pasini
18. Michele Pirro
19. James Ellison
20. Ivan Silva
21. Danilo Petrucci
22. Steve Rapp